* we know from edge slopes, that the X offset is calculated with a reciprocal and not a 'proper' division. for example: slope with dx=2 and dy=96. x isn't incremented until y=49 (would be 48 with proper division).

* trying to figure out the reciprocal. its precision, how it's calculated (proper 1/X division? Newton-Raphson? LUT?)


* Z interpolation along Y loses precision for whatever reason. Z range 0-0x800000 loses 14 bits, 0-0x400000 loses 13 bits, 0-0x200000 loses 12 bits and so on. except: 0-0x200 still loses 2 bits. weird.

* Z interpolation along X seems to have full precision. (losing two bits, but I think fog is losing them)

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Kuribo64